It's like people forget that Wlad won 5 rounds off Fury, or that Steve Cunningham decked him. Fury is not invincible.
Muhammad Ali got decked by 2 guys early in his career that wouldn't have been fit to lace his boots a few years later. Ken Norton won a bunch of rounds off him and Norton isn't in Wlads league. Nobody is invincible but Fury delivers the goods in the big fights. He's huge, he is skilled and has an ATG heart/will to win. That's more than enough to become a modern great.